I'm Considering Bitcoin Mining

The real risk, at least for BTC, is that it's just not efficient for you and that your'e likely to spend more money on electricity.

1. Back in the day, you could use CPU's
2. People switched to GPU's, and for some currencies / price levels it makes sense
3. Now, people have dedicated ASIC's

In short, it's not super efficient by any means.

Further, some currencies are moving away from PoW (proof-of-work).